The present invention generally relates to a flat cable connector, and more particularly to one with improved mounting characteristics.
Conventional flat cable connectors are used to connect flat flexible cables called flexible printed circuit (FPC), flexible flat cable (FFC) or the like, as shown in Japanese Patent Application Laid-Open (Kokai) Publication No. 2002-270290.
FIG. 17 is a cross-sectional view of such a conventional cable connector.
As shown in FIG. 17, the connector includes a housing 301 made from an insulating material, a plurality of conductive terminals 302 which are held by the housing 301, and an actuator 303, also made from an insulating material, which is secured to the housing 301 so that the actuator 303 can move relative to the housing 301. The connector is mounted on a substrate 304 such as a circuit board, and a flat cable 305 inserted in an opening of the housing 301 is connected to the cable connector. Each of the terminals 302 has an H-shape, and includes an upper portion 306 that extends on the upper side of the terminal 302 in the insertion direction of the flat cable 305, a lower potion 307 that extends on the lower side of the terminal 302 in the insertion direction of the flat cable 305, and a thin and long belt-shaped connecting spring portion 308 for connecting the middle parts of the upper portion 306 and the lower portion 307 together. A tail portion 310 projected downward is connected in a manner such that it is fixed by solder to a connecting pad (not shown) formed on the surface of the substrate 304 by the use of reflow solder.
When the actuator 303 is at an open position as shown in FIG. 17, a space formed between a contacting portion 311 of the terminal upper portion 306 and a contacting portion 312 of the terminal lower portion 307 of each of the terminals 302 expand so that the flat cable 305 can be inserted into or removed from the housing opening. Once the actuator 303 is moved from the open position to a closed position while the flat cable 305 is inserted into the space between the terminal contacting portions 311 and 312, an oval-shaped rotation shaft 309 rotates and the rear portions of the upper portion 306 and the lower portion 307 of the terminal 302 are pushed apart from each other. Therefore, the space between the contacting portion 311 of the terminal upper portion 306 and the contacting portion 312 of the terminal lower portion 307 is narrowed and the flat cable 305 is sandwiched between them. Accordingly, conductive leads (not shown) of the flat cable 305 contact the contacting portions 311, 312 and are connected to the terminals 302. In this case, as the connecting spring portion 308 is elastically deformed, the terminal upper portion 306 rotates counterclockwise about a connecting point where it is connected to the connecting spring portion 308, and the terminal contacting portion 311 of the upper portion 306 moves downward to thereby sandwich the flat cable 305 in between it at the contacting portion 312 of the lower portion 307.
However, in the conventional cable connector, when the tail portion 310 is connected to the connecting pad on the surface of the substrate 304 by the use of reflow solder, flux component contained in the solder may creep up along the side surfaces of the terminals 302, causing a flux-creep-up and contamination problem. Once the flux adheres to the terminal contacting portions 311 and 312, a failure in contact occurs between the contacting portions 311 and 312, and the cable conductive leads, which results in losing electrical conduction between the terminals 302 and the cable leads. The flux, after solidifying, bonds the upper portion 306 and a wall of the housing 301, and accordingly the upper portion 306 becomes unable to rotate.
This problem occurs for the reason that when the terminals 302 are fitted into accommodating grooves of the housing 301, the flux creeps up similar to capillary action, and enters gaps between the terminals 302 and the accommodating grooves. Since molten flux has a higher fluidity than the molten solder, it can flow through even a tiny gap that solder could not pass through. Therefore, even though a creep-up of the solder can be prevented, it has been difficult to ensure prevention of a creep-up of flux.